fix: --json no longer suppresses the residual-signal exit code (#30)

clean_file.py and clean_image.py computed the failure exit code inside
the human-output branch, so `--json` always exited 0 even when the clean
left C2PA/AI signals behind. A script gating on `clean_file --json` would
treat a still-marked file as clean.

Move the residual (and degraded-PDF) decision out of the output branch in
both entry points so the exit code is the same regardless of --json.
Human output is unchanged; degraded best-effort PDF copies stay
non-failures.

Adds tests asserting json and human modes return the same exit code for
residual, clean, and degraded cases.

Co-authored-by: Claude Opus 5 <noreply@anthropic.com>

skills/remove-ai-marks/scripts/clean_file.py

@@ -148,16 +148,16 @@ def main() -> int:
             eprint(f"error: {e}")
             return 1
         result = {"kind": "image", **result}
+        residual = result["still_has_c2pa"] or result["still_has_ai_metadata"]
         if args.json:
             print(json.dumps(result, indent=2))
         else:
             eprint(f"wrote {result['output']} ({result['bytes_in']} -> {result['bytes_out']})")
             for a in result["actions"]:
                 eprint(f"  - {a}")
-            if result["still_has_c2pa"] or result["still_has_ai_metadata"]:
+            if residual:
                 eprint("warning: residual C2PA/AI signals may remain")
-                return 1
-        return 0
+        return 1 if residual else 0
 
     try:
         result = clean_container(src, dest)
@@ -165,21 +165,20 @@ def main() -> int:
         eprint(f"error: {e}")
         return 1
     result = {"kind": "container", **result}
+    residual = result["still_has_c2pa"] or result["still_has_ai_metadata"]
+    degraded = bool(result.get("meta", {}).get("degraded"))
     if args.json:
         print(json.dumps(result, indent=2, ensure_ascii=False))
     else:
         eprint(f"wrote {result['output']} format={result['format']}")
         for a in result["actions"]:
             eprint(f"  - {a}")
-        if result["still_has_c2pa"] or result["still_has_ai_metadata"]:
+        if residual:
             eprint("warning: residual C2PA/AI signals may remain")
             for f in result.get("post_findings") or []:
                 eprint(f"  ! {f}")
-            # degraded PDF copy is not a hard failure if we only warn
-            if result.get("meta", {}).get("degraded"):
-                return 0
-            return 1
-    return 0
+    # A degraded (best-effort) PDF copy warns but is not a hard failure.
+    return 1 if (residual and not degraded) else 0
 
 
 if __name__ == "__main__":

skills/remove-ai-marks/scripts/clean_image.py

@@ -109,6 +109,10 @@ def main() -> int:
         eprint(f"error: {e}")
         return 1
 
+    pr = result.get("pixel_removal")
+    residual = result["still_has_c2pa"] or result["still_has_ai_metadata"]
+    failed = residual or (pr is not None and not pr.get("available"))
+
     if args.json:
         print(json.dumps(result, indent=2))
     else:
@@ -129,24 +133,16 @@ def main() -> int:
                 f"confidence {result['synthid_after'].get('confidence', 0.0):.3f} "
                 f"(watermarked: {label})"
             )
-        pr = result.get("pixel_removal")
         if pr is not None:
             if pr.get("available"):
                 eprint(f"CtrlRegen: removed on {pr.get('device', 'unknown device')}")
             else:
                 eprint(f"CtrlRegen: unavailable: {pr.get('error', 'unknown error')}")
-
-        failed = False
-        if result["still_has_c2pa"] or result["still_has_ai_metadata"]:
+        if residual:
             eprint("warning: residual C2PA/AI signals may remain")
             for f in result.get("post_findings") or []:
                 eprint(f"  ! {f}")
-            failed = True
-        if pr is not None and not pr.get("available"):
-            failed = True
-        if failed:
-            return 1
-    return 0
+    return 1 if failed else 0
 
 
 if __name__ == "__main__":

tests/test_json_exit_code.py

@@ -0,0 +1,92 @@
+"""--json must not suppress the residual-signal exit code (was: always 0)."""
+
+from __future__ import annotations
+
+import sys
+from pathlib import Path
+
+ROOT = Path(__file__).resolve().parents[1]
+SCRIPTS = ROOT / "skills" / "remove-ai-marks" / "scripts"
+sys.path.insert(0, str(SCRIPTS))
+
+import clean_file  # noqa: E402
+import clean_image  # noqa: E402
+
+
+def _container_result(dest: Path, residual: bool, degraded: bool = False) -> dict:
+    return {
+        "input": "x.md",
+        "output": str(dest),
+        "format": "markdown",
+        "actions": ["clean"],
+        "bytes_in": 1,
+        "bytes_out": 1,
+        "still_has_c2pa": residual,
+        "still_has_ai_metadata": residual,
+        "post_findings": ["marker:c2pa"] if residual else [],
+        "meta": {"degraded": degraded},
+    }
+
+
+def _run_clean_file(monkeypatch, tmp_path, *, json_flag, residual, degraded=False):
+    src = tmp_path / "x.md"
+    src.write_text("---\ngenerator: Claude\n---\nhi\n", encoding="utf-8")
+    dest = tmp_path / "x.cleaned.md"
+    monkeypatch.setattr(
+        clean_file, "clean_container", lambda *a, **k: _container_result(dest, residual, degraded)
+    )
+    argv = ["clean_file.py", str(src), "-o", str(dest)]
+    if json_flag:
+        argv.append("--json")
+    monkeypatch.setattr(sys, "argv", argv)
+    return clean_file.main()
+
+
+def test_clean_file_json_and_human_agree_on_residual(monkeypatch, tmp_path):
+    # The bug: --json returned 0 while human mode returned 1.
+    assert _run_clean_file(monkeypatch, tmp_path, json_flag=False, residual=True) == 1
+    assert _run_clean_file(monkeypatch, tmp_path, json_flag=True, residual=True) == 1
+
+
+def test_clean_file_json_and_human_agree_on_clean(monkeypatch, tmp_path):
+    assert _run_clean_file(monkeypatch, tmp_path, json_flag=False, residual=False) == 0
+    assert _run_clean_file(monkeypatch, tmp_path, json_flag=True, residual=False) == 0
+
+
+def test_clean_file_degraded_pdf_is_not_a_failure_in_either_mode(monkeypatch, tmp_path):
+    assert _run_clean_file(monkeypatch, tmp_path, json_flag=False, residual=True, degraded=True) == 0
+    assert _run_clean_file(monkeypatch, tmp_path, json_flag=True, residual=True, degraded=True) == 0
+
+
+def _image_result(dest: Path, residual: bool) -> dict:
+    return {
+        "input": "x.png",
+        "output": str(dest),
+        "actions": ["strip"],
+        "bytes_in": 1,
+        "bytes_out": 1,
+        "still_has_c2pa": residual,
+        "still_has_ai_metadata": residual,
+        "post_findings": ["byte-scan c2pa"] if residual else [],
+        "synthid_before": None,
+        "synthid_after": None,
+        "pixel_removal": None,
+    }
+
+
+def _run_clean_image(monkeypatch, tmp_path, *, json_flag, residual):
+    src = tmp_path / "x.png"
+    src.write_bytes(b"\x89PNG\r\n\x1a\n")
+    dest = tmp_path / "x.cleaned.png"
+    monkeypatch.setattr(clean_image, "clean_image", lambda *a, **k: _image_result(dest, residual))
+    argv = ["clean_image.py", str(src), "-o", str(dest)]
+    if json_flag:
+        argv.append("--json")
+    monkeypatch.setattr(sys, "argv", argv)
+    return clean_image.main()
+
+
+def test_clean_image_json_and_human_agree_on_residual(monkeypatch, tmp_path):
+    assert _run_clean_image(monkeypatch, tmp_path, json_flag=False, residual=True) == 1
+    assert _run_clean_image(monkeypatch, tmp_path, json_flag=True, residual=True) == 1
+    assert _run_clean_image(monkeypatch, tmp_path, json_flag=True, residual=False) == 0